A terminal device such as a PC has conventionally transmitted all traffic data from applications used for the terminal device regardless of applications from which the traffic data comes, to a wireless link via a modem function of a mobile terminal. Therefore, an application such as an Internet phone and video communication that should guarantee end-to-end real-time service transmits and receives session information of the application using Session Initiation Protocol (SIP). Here, in the case where the application is executed on a mobile device, the mobile device can control and monitor creation, modification, and deletion of the session.
However, in the case where the application is executed on a terminal device, and the mobile device serves as only a modem, the mobile device processes data coming from the terminal device and transmits the processed data to a link only. At this point, since the mobile device is not aware of a service being executed on the data, the mobile device realizes a predetermined interface with an application executed on the terminal device, and performs a request for opening a wireless link suitable for real-time service in order to execute the real-time service.
However, the application of the terminal device executed in this method is not universally used but is peculiar to the software of the mobile device. Therefore, since a different application is used depending on a mobile device through which the service is executed, much inconvenience is generated.
FIGS. 1A and B are illustrating a construction of providing data service in real-time through a mobile device in a conventional wireless communication system.
The wireless communication system includes a terminal device 101, a mobile device 103, and a wireless network device 105. Referring to FIG. 1A, the terminal device 101 sequentially transmits all data to the mobile device 103 without discriminating applications. Therefore, the system has a limitation of not guaranteeing the QoS of an application being executed.
To resolve the above limitation, a method illustrated in FIG. 1B has been used. In the method, all traffic data transmitted from the terminal device 101 are discriminated, and when a wireless link status is poor, traffic data of respective applications are discriminated in a transmission queue and packets corresponding to real-time service are transmitted first.
Referring to FIG. 1B, information as to the QoS of service provided by an application executed on the terminal device 101 is transmitted through special control frames 110, 112, and 114.
After that, the mobile device 103 analyzes the special control frames 110, 112, and 114 through a module 116 communicating with the terminal device, requests a wireless link resource suitable for the QoS, receives a new resource suitable for the application, and obtains a packet classifier to be mapped to the resource.
After that, data received from the terminal device are classified by the packet classifier, and transmitted to the new resource, so that the QoS is guaranteed.
However, though the above-described method guarantees the QoS of the application, a method of receiving QoS confirmation from the terminal device 101 involves a special process of having to directly modify the application software, so that the method is not universally used and is limited in its usage.